The overall goals of this research project are to identify the molecular and cellular factors that play a role in the development of the sensory epithelium of the mammalian cochlea (the organ of Corti). The organ of Corti is comprised of at least 6 distinct cell types that are arranged in highly conserved mosaic. The generation of a specific number of each cell type and the arrangement of these cell types into a regular pattern are essential for the normal perception of sound, however our understanding of the factors that play a role in the development of this structure is extremely limited. This project was initiated at the beginning of March, 2000. Therefore at the time of this writing, the project has only been underway for 5 months. In the last 5 months we have identified two genes that may play key roles in the regulation of cellular pattern in the organ of Corti. First, Myt1 a gene that has been shown to play a role in lateral inhibition was found to be expressed in cells that will develop as sensory hair cells. This suggests that Myt1 may play a role in the inhibitory interactions that mediate the formation of an alternating mosaic of hair cells and non-sensory supporting cells. Second we have found that Sox-2, a gene that is required for primary neural induction, is also expressed in the developing cohlear sensory epithelium and may therefore play a similar role in the development of this portion of the auditory system.